Due to the advantages such as light and thin design, low power consumption and no radiant pollution, Liquid Crystal Display (LCD) is now widely applied to products such as TV set, notebook computer, mobile phone and personal digital assistant, etc.
At present, liquid crystal display devices of commercially available electronic products with a touch display function are generally divided into resistive, capacitive, infrared ray and ultrasonic liquid crystal display devices, among which the capacitive touch display screen has the widest application. The capacitive touch display screens mainly include on-cell touch display screens and in-cell touch display screens in which a touch screen embedded into a display module. Regardless of an on-cell touch display screen or an in-cell touch display screen, the structure of the screen includes a protection cover plate, as well as a touch unit and a display panel that are located under the protection cover plate. A common protection cover plate is made of toughened glass, has a high surface hardness and a good frictional resistance, and hence can protect the touch sensing components and the display components thereunder.
No matter it is an add-on touch display device or an in-cell touch display device, the protection cover plate thereof generally includes a display region and a peripheral non-display region, a touch key region is usually located in the non-display region outside the display region of the protection cover plate, and a touch key electrode is provided in the touch key region.
In the related art, as shown in FIG. 1, each of touch key electrodes 2211 provided on the back of a protection cover plate needs to be connected with an external flexible circuit board 44 via a respective lead 43 so as to independently transmit a touch signal to the control circuit. Therefore, a line manufacturing process, an adhering process and also a flexible circuit board binding process are required, leading to complicate processes, complex structures, and high manufacturing costs.